The most striking difference is in the outline of the head; the alligator has a broad, rounded snout, while that of the crocodile is narrower and more pointed (Fig. 2). Again, in the crocodile the fourth tooth from the front projects slightly outwards and fits into a notch in the side of the upper jaw, while in the alligator (also in the caiman) the corresponding tooth on each side fits into a socket in the upper jaw and hence is hidden, except in some old animals with very long teeth, in which it may pierce the upper jaw and show from above. According to Ditmars, the crocodile has, as a rule, larger and more exposed teeth than the alligator. Finally, as will be brought out later, the crocodile is usually more quick and active, and also more vicious, than the alligator. Very young alligators are nearly black, with distinct, yellow cross bands; as they grow older these markings become less distinct until in maturity the animals are of a uniform gray or dirty black color. _Habitat._ The American alligator is found in the rivers and swamps of the Southern States, from the southern part of North Carolina to the Rio Grande, though Florida is usually thought of as being the region in which they particularly abound. Years ago, before the rifle of the ubiquitous tourist and so-called sportsman had gotten in its deadly work, the alligators were probably very abundant in the Southern States; but they have been so ruthlessly destroyed by native hunters for their skins, and by others for mere wanton sport, that one may travel, perhaps, for days along the rivers of the South without seeing a single ’gator. The account quoted by Clarke from Bartram’s travels of more than one hundred years ago, while probably exaggerated, gives an idea of the abundance of the alligators at that time: “The rivers at this place from shore to shore, and perhaps near a half mile above and below me, appeared to be one solid bank of fish of various kinds, pushing through the narrow pass of San Juans into the little lake on their return down the river, and the alligators were in such incredible numbers, and so close together from shore to shore, that it would have been easy to have walked across their heads, had the animals been harmless.” At the present time it is usually necessary to travel far from the usual routes of the Northern tourists to find alligators in any abundance.